The present disclosure relates to an assembly for mounting a rotating cutting blade to a driven arbor. The assembly has particular applicability to miter saws, table saws and circular saws incorporating a rotating blade.
A typical miter saw, such as the saw 10 shown in FIG. 1, includes a rotating blade 12 supported relative to a work table 14. In the case of the miter saw, the blade may be oriented at various multi-planar angles relative to a workpiece to be cut. The rotating blade is mounted to an arbor 16 (FIG. 2) that is rotated by an associated motor.
A typical blade mounting assembly, as depicted in FIG. 2, includes an inner washer 30 that is mounted on a spindle 18 of an arbor 16 of the rotary power source for the saw 10. The washer 30 thus includes a central bore 30a to receive the spindle. One face 32 of the inner washer bears against a shoulder 20 defined by the arbor at the base of the spindle. The opposite face 34 bears against the right face 13R of the blade 12, which also includes a bore 12a for mounting on the spindle.
An outer washer 40 is mounted at its central bore 40a on the spindle so that the inside face 42 bears against the opposite outside or left face 13L of the blade. (In accordance with standard terminology in the art, the right side of the blade faces the rotating spindle, while the left side faces away from the spindle). An arbor washer 50 with corresponding bore 50a is seated against the outside face 44 of the outer washer 40. The entire assembly is clamped together by a blade bolt 60 that threadedly engages a threaded bore 19 in the spindle. The head 62 is sized to bear against the arbor washer to thereby sandwich the rotating blade 12 between the inner and outer washers 30, 40.
With this mounting arrangement, the right face 13R of the blade is the locating face for the blade. In other words, the position of the right face 13R is always determinant regardless of the thickness of the blade 12, and is always in a fixed position or at a fixed axial distance relative to the shoulder 20 of the arbor 16. The position of the left face 13L is dependent upon the thickness of the blade. This thickness is variable due to manufacturing tolerances or the designed thickness of the blade. For many rotary saw applications, this variability of position of the left face of the cutting blade is not a significant concern. However, in certain applications, such as a miter saw, much of the cutting action of the blade occurs at the left or outer face, rather than at the right face, of the blade 12. In these applications the variability of the left face position leads to variability in the cut location, which, depending upon the degree of variability can result in an improper cut.
One problem with this left side variability arises when projecting a cut line on the workpiece. In many saws the cut line is projected at the left side of the blade to avoid visual conflict with the spindle and rotary power source. The cut line can typically be established for one predetermined blade thickness. If a thicker or thinner blade is used to make the cut, the left side cutting action of the blade will be axially offset from the desired cut line. The present disclosure provides a solution to this and other problems by establishing a fixed axial location for the left side of the blade.